Pelagic thresher
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[Photo] A pelagic thresher shark swimming over the bottom of a reef. Photo by http://en.wikipedia.org/wiki/User:Spotty11222

The pelagic thresher, Alopias pelagicus, is a thresher shark of the genus Alopias, found in tropical oceans, at depths down to 500 m. It was first described in 1935 by Japanese ichthyologist Hiroshi Nakamura.

Reproduction and growth
The pelagic thresher reproduces via ovoviviparity, this is where the embryo is nourished in the yolk sac, in later development the unborn shark is feed on ovulated eggs a process known as oophagy. At birth the young measure around 5.2 to 6.2 ft. The gestation period is unknown. The average size of the pelagic is 10 feet and a weight of 153 lb. Males reach maturity at 7 or 8 years of age, while females reach maturity at 8 or 9 years of age. In the wild the pelagic thresher can live for approximately 16 years.

Habitat and diet
The pelagic thresher prefers open ocean where they can be found from the surface to depths of around 492 ft. They are abundant of the north-east coast of Taiwan and North American waters around California and Mexico. Their full distribution is unknown due to confusion with the long-tailed thresher, Alopias vulpinus. The pelagic thresher's preferred food are herring, flying fish and pelagic squid. They use their extremely long upper caudal fin in a whip-like fashion to stun their prey.

Conservation
Currently being exploited by the fishing industry and is classed as vulnerable, but is not yet a protected species. It was first assessed by the IUCN in 2007, gaining a vulnerable status.

http://en.wikipedia.org/wiki/Pelagic_thresher

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